Caption: Close-up of a giant, yellow slime mould (class Myxomycetes) in the vegetative phase, growing on the bark of a tree. Slime moulds are commonly found on moist, decaying wood and other organic substrata. They are grouped together with the Fungi but are probably not related. In this phase the slime mould consists of multinucleate naked masses of protoplasm, known as plasmodia, which in this species are organised in a vein-like network. The cytoplasm flows in these structures at a rate of about 1mm per second. The plasmodia feed by engulfing bacteria and fungal cells and under favourable conditions they give rise to spores.